Linked Life Data

11389595

Source:http://linkedlifedata.com/resource/pubmed/id/11389595

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
2001-6-6
pubmed:abstractText
Lipoxygenases are key enzymes in the metabolism of unsaturated fatty acids. Soybean lipoxygenase-1 (LOX-1), a paradigm for lipoxygenases isolated from different sources, is composed of two domains: a approximately 30 kDa N-terminal domain and a approximately 60 kDa C-terminal domain. We used limited proteolysis and gel-filtration chromatography to generate and isolate a approximately 60 kDa fragment of LOX-1 ("mini-LOX"), produced by trypsin cleavage between lysine 277 and serine 278. Mini-LOX was subjected to N-terminal sequencing and to electrophoretic, chromatographic, and spectroscopic analysis. Mini-LOX was found to be more acidic and more hydrophobic than LOX-1, and with a higher content of alpha-helix. Kinetic analysis showed that mini-LOX dioxygenates linoleic acid with a catalytic efficiency approximately 3-fold higher than that of LOX-1 (33.3 x 10(6) and 10.9 x 10(6) M(-1) x s(-1), respectively), the activation energy of the reaction being 4.5 +/- 0.5 and 8.3 +/- 0.9 kJ x mol(-1) for mini-LOX and LOX-1, respectively. Substrate preference, tested with linoleic, alpha-linolenic, and arachidonic acids, and with linoleate methyl ester, was the same for LOX-1 and mini-LOX, and also identical was the regio- and stereospecificity of the products generated thereof, analyzed by reversed-phase and chiral high-performance liquid chromatography, and by gas chromatography/mass spectrometry. Mini-LOX was able to bind artificial vesicles with higher affinity than LOX-1, but the binding was less affected by calcium ions than was that of LOX-1. Taken together, these results suggest that the N-terminal domain of soybean lipoxygenase-1 might be a built-in inhibitor of catalytic activity and membrane binding ability of the enzyme, with a possible role in physio(patho)logical conditions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6819-27
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Tryptic digestion of soybean lipoxygenase-1 generates a 60 kDa fragment with improved activity and membrane binding ability.
pubmed:affiliation
Department of Experimental Medicine and Biochemical Sciences, University of Rome, Tor Vergata, Rome, Italy. maccarone@med.uniroma2.it
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't